Expansible bit.



J. G. PASSAUER.

EXPANSIBLE BIT.

APPLICATION FILED NOV. 13. l9l5.

Patented Nov. 28, 1916.

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EXPANSIBLE BIT.

Application filed November 13. 1915.

To all whom it may concern Be it known that I, JOHN G. PAssAUnR, a citizen of the United States, residing at Tionest-a, in the county of Forest and State of Pennsylvania, have invented new and useful Improvements in Expansible Bits, of which the following is a specification.

This invention relates to attachments for boring bits by means of which the diameter of the bore cut by the bit may be increased.

The primary object of the invention is to provide means cooperating with the well known form of bit having the inherent property of cutting behind the blade of the bit a bore of greater diameter than the bore out by the blade of the bit.

An object of the invention is to provide simple and well constructed means for moving the cutting elements of the attachment toward or away from the body of the bit for increasing or decreasing the size of the out.

lVith these and other objects in view the invention consists in the construction, combination and arrangement of parts as will be hereinafter more fully described, illustrated in the accompanying drawing and pointed out in the claim hereunto appended.

In the drawing :Figure l is a side elevation of a bit showing my invention applied thereto. Fig. 2 is a longitudinal section therethrough. The remaining figures are detail views.

Referring to the drawing the numeral 1 designates the shank of a bit shown in this particular instance as being hollow throughout its length. One end of the shank is closed while the remaining end is open and in this open end is arranged a bearing 1.

The numeral 2- designates the cutting blade while the numeral 3 designates the threaded point or tip of the bit.

Mounted for rotation within the shank is a shaft l having one end protruding beyond one end of the shank 1 as indicated at 5 and squared so that an instrument may be attached thereto for giving rotatable movement to the shaft. For preventing movement of the shaft at predetermined times I provide a thumb screw 6 secured into the shank 1 and engaging the shaft 4. The

Specification of Letters'Patent.

Patented Nov. 28. 1916.

Serial No. 61,361.

other end of the shaft 4 is mounted in the bit at the blade 2 while adjacent this end the shaft is provided with gear teeth 7 properly meshing with teeth 8 formed on the opposing faces of jaws 9. These jaws are slidably mounted in the shank 1 in a transverse direction with relation to the passage in the shank and as shown each jaw is provided at its end with a cutting edge 10. At this point attention is called to the fact that the jaws 9 are arranged just in the rear of the blade 2 with the result that the cutting edges of the jaws will only have to cut the surplus material necessary to enlarge the bore as the cutting blade cuts the bulk of the material in its passage.

From the foregoing description it will be seen that when an instrument is applied to the squared end of the shaft and rotation given to the latter, the jaws will be fed outwardly or inwardly depending entirely upon the direction in which the shaft is rotated with the result that I can accurately regulate the size of openings made by the jaws.

A very important advantage of my device is that the size of a. bore can be increased after once being cut by a bit of smaller diameter.

From the foregoing description taken in connection with the accompanying drawing. the advantages of the construction and the method of operation will. be readily apparent to those skilled in the art to which the invention relates, and while I describe the principle of the operation of the invention together with the device that I now consider to be the best embodiment thereof, I desire to have it understood that the device shown is merely illustrative and that such changes may be made when desired as are within the scope of the claim.

hat I claim is A bit comprising a cylindrical hollow shank having one end open. a bearing detachably mounted in the open end and extending beyond the end whereby said shank may be rotated, a shaft rotatably mounted in said bearing and having one end mounted in the wall of the closed end of the shank.

a pair of jaws slidably mounted in the shank end of the latter, and a set screw mounted in a right-angular direction With relation in said shank and engaging an intermediate to said shaft, a gear secured to said shaft portion of said shaft at a point adjacent and engaging teeth formed on said jaws, said bearing.

said gear and shaft being insertible into In testimony whereof I aflix my signature. the interior of the shank through the open J. G. PASSAUER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

